Association of swim distance and age with body composition in adult female swimmers.

PURPOSE: The purpose of this investigation was to examine the relationship between average weekly swimming distance and age with body composition in adult female endurance swimmers.
METHODS: Thirty-five women, aged 21-73 yr, volunteered to participate. Weekly swimming distance was determined from a self-reported exercise log. Body composition was estimated by dual-energy x-ray absorptiometry (DXA), waist circumference, abdominal sagittal diameter, and skinfold thickness measures. Associations between swimming distance and age with body composition were examined using regression analysis.
RESULTS: Swimming distance had shared variances as follows: 23% with percent body fat, 26% with waist circumference, 20% with abdominal sagittal diameter, and 20%, 24%, and 22% with subscapular, suprailiac, and triceps skinfolds, respectively. Abdominal sagittal diameter was the only adiposity measure demonstrating a stronger relationship with age (R2 = 0.29, P = 0.00) than with swimming distance (R2 = 0.20, P = 0.03). Bone mineral content was linearly related to swimming distance and age having a negative association with age (r2 = 0.18, P = 0.01) and a positive one with swimming distance (r2 = 0.12, P = 0.05). In addition, there was a negative linear association observed between swimmer age and bone mineral density (r2 = 0.12, P = 0.05).
CONCLUSION: In these female adults, endurance swimming was mildly associated with body adiposity. Age was not associated with body fat mass independently from swimming activity except with that measure reflecting abdominal visceral fat deposits. These data suggest that greater fat mass in female swimmers is more strongly related to lower levels of exercise than to age but that there is an additional influence of age on fat accumulation in the intra-abdominal area of the body.